This invention relates to an apparatus which reduces the rolling speed of cylindrical articles, for example, pipes, rods or the like on inclined skid rails.
In parts of ironworks where cylindrical articles are manufactured, several kinds of roller conveyor lines are installed for the purpose of transporting the articles, inside of factories. The lines are often coupled to one another via skid rails. The skid rails are used for several purposes, for instance, changing the relative direction between the lines and temporary storing of the articles for inspection.
The skid rails, however, have certain disadvantages. The pipes or the like rapidly roll fast on the rails and collide violently with one another especially when they are being stopped for rolling at the outlet of the rails. As the result, the cylindrical articles make high intensity sounds which result in considerable discomfort not only to the workers but also to the neighbors living near to the factories being operated day and night. In many jurisdictions, laws and regulations have been enacted to oblige the owner or the managers of factories to reduce the level of noise. Accordingly, effective methods and apparatus are now desirable and often required to reduce noise levels required. Various apparatuses have been devised in order to reduce noise.
For instance, an apparatus using electromagnetic devices has been proposed in which many electromagnetic coils and proximity switches are mounted at intervals adjacent the skid rails. These coils are alternately empowered when the switches detect the position of the cylindrical articles to be stopped. However, this known apparatus is expensive to construct and install and to operate because the apparatus is complicated in structure and consumes considerable electric power. The cylindrical articles become magnetised by the apparatus and the residual magnetism may exert, in many cases, undesirable influence in following process steps and uses. Furthermore, the apparatus cannot be used for pipes or the like made of non-magnetic materials, for example, stainless steel.
Another type of apparatus also has been proposed in which an endless chain located near to skid rails is rotated in the same direction of the transportation of pipes or the like. Many braking attachments are provided at regular intervals along the chain. The heads of the attachments protrude above the skid rails so that they can act as brakes while the cylindrical articles slowly roll on the rails. The disadvantages of this type of known apparatus are caused by the fixed placement intervals of the attachments. When a kind of pipe whose diameter is slightly greater than the interval is dealt with, many pipes extend in a row and in contact with one another to load some attachment with too much weight. On the contrary, when the diameter of the pipes is much smaller than the interval, the attachments lose smoothness in their braking action.
There has been proposed still another apparatus in which a considerable number of flexible spring plates are fixed to a base plate in parallel with the skid rails. The heads of the spring plates are projected above the skid rails to brake pipes rolling on the skid rails. Although the degree of the projection is adjustable, it is difficult to gain always an optimum resiliency effect. Smaller pipes are likely to be repelled backwards.